1. Field
Embodiments relate to a pixel, a display device, and a driving method thereof, and, more particularly, to a display device capable of controlling an output range of a data driving IC and a driving method thereof.
2. Description of the Related Art
An organic light emitting diode display uses an organic light emitting diode (OLED) in which luminance is controlled by current or voltage. The organic light emitting diode (OLED) includes a positive electrode layer and a negative electrode layer forming an electric field and an organic light emitting material emitting light by the electric field.
Generally, organic light emitting diode (OLED) displays are classified into a passive matrix OLED (PMOLED) and an active matrix OLED (AMOLED) according to a mode driving the organic light emitting diode (OLED). The AMOLED devices that control light emission for each unit pixel are superior from the viewpoint of resolution, a contrast, and operation speed, and have become the most commonly used.
One pixel of the active matrix OLED includes an organic light emitting diode (OLED), a driving transistor controlling a current amount supplied to the organic light emitting diode (OLED), and a switching transistor transferring data voltage controlling a light emitting amount of the organic light emitting diode (OLED) as the driving transistor. The light emitting amount of the organic light emitting diode (OLED) is determined according to the current amount controlled by the driving transistor.
Image quality of a display panel may be determined according to how accurate the driving transistor included in each of a plurality of pixels controls the current amount according to the data voltage. However, threshold voltages of driving transistors substantially deviate due to precision limitation of a producing process. The threshold voltage deviation between the driving transistors included in one display panel may not be significant, while the threshold voltage deviation between driving transistors between different display panels may be significant. For example, the threshold voltage of the driving transistors in one display panel may be −1 V, while threshold voltage of the driving transistors in another display panel may be −4 V.
As one method for compensating the threshold voltage deviation of the driving transistor, the data driving IC may output data voltage in which a compensation value for compensating the threshold voltage deviation of the driving transistor is reflected to compensate the threshold voltage deviation of the driving transistor. However, the data voltage in which the compensation value is reflected may exceed an output range of the data driving IC. For example, the data voltage in which the compensation value is reflected in the display panel in which the threshold voltage is substantially −1 V may be within the output range of the data driving IC, but the data voltage in which the compensation value is reflected in the display panel in which the threshold voltage is substantially −4 V may exceed the output range of the data driving IC. When the data voltage in which the compensation value is reflected exceeds the output range of the data driving IC, the threshold voltage deviation of the driving transistor is not normally compensated and deterioration in image quality due to the threshold voltage deviation of the driving transistor may occur. In order to solve the problem, a data driving IC having a sufficiently wide output range needs to be used. However, the data driving IC having the wide output range increases power consumption and cost.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.